Benefit: You gain a +1 bonus on all attack rolls you make using the selected special weapon material. This bonus stacks with other bonuses on attack rolls, including the one from Weapon Material Focus.

Special: You can gain Greater Weapon Material Focus multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon material.
A fighter may select Greater Weapon Focus as one of his fighter bonus feats.